Semiconductor
Blazed Diffraction Gratings
EUV - Blazed Diffraction Gratings for OEMS
Inprentus offers custom master blazed diffraction gratings for EUV applications where optimization of optical efficiency, instrument compactness, and performance are priorities for next generation processing labs. Inprentus has the ability to manufacture blazed diffraction gratings with extreme focusing abilities using high variable line spacing (VLS). This leads to optimization towards reduced spot size and brighter light at the operating wavelength. The gratings can be used in and around design wavelengths in a wide variety of sizes and specifications, enabling compact instrument designs and upgrades. Inprentus also works closely with customers to provide custom blaze angles in the blazed diffraction grating masters to enable a drop-in replacement in a current instrument or next-generation instrument upgrade.
“Inprentus gratings have been key to enabling our company to create an entirely new product offering”
EUV Tech, Martinez, CA
Blazed Diffraction Grating Specifications
- Blaze angles from 0.1° to 80°
- VLS - Variable Line Spacing (VLS)
- Echelle gratings
- Ruling on curved substrates – concave, toroidal, elliptical
- Resolving power above 100,000 (dependent on other specifications)
- High damage threshold substrates and overcoatings available
- Dimensions up to 500 x 200mm
- Line densities from 50 to 3000 l/mm
- Gold (Au) coated ruling surface with silicon or fused silica substrates
Performance: High Grating Efficiency
Inprentus 824 lpmm custom EUV grating with extreme VLS was verified to provide near-ideal
efficiency at design wavelength. Compare to simulated efficiency in figure 4. The measurement
was performed at the Center for X-Ray Optics at Lawrence Berkeley National Laboratory.
Upgrades: Extreme Focusing
Focused image size can be reduced by around 50x and the instrument made smaller using high
VLS gratings. Efficiency measured at different points on a high VLS grating is shown. The
differences are consistent with designed high line density variation. Inprentus has experience with
manufacturing blazed diffraction gratings with line spacing variation of 100% and more.
Nanomanufacturing: Precision Blaze Angle
Manufacturing advancements have enabled this EUV VLS grating to have line density extrema
ranging from 736 lpmm to 930 lpmm while maintaining a blaze angle of 3.3° +/- 0.04°. An
atomic force microscope (AFM) grayscale height map of manufactured grooves is shown below
along with groove profile in blue.
Support Capabilities: Efficiency Simulation
Proprietary simulation allows manufacturing setup to be precisely modified until the grating
yields efficiency (orange) above 80% (grey) of theoretical (black) efficiency. Simulated efficiency
is included in the FAT report and agrees with measured performance.